1. Field of the Invention
The present invention relates to a microbubble generator.
2. Description of the Related Art
It is known that, when washing various items and showering pets, using water mixed with an innumerable number of microbubbles with a size of 10 to 50 micrometers is highly effective in removing dirt and grime. In recent years, the same effect has also been confirmed with showers for human use. Previously, as a microbubble generator for generating microbubbles, a shower head containing a Venturi tube in its base portion has been proposed (for example, see Japanese patent document JP-A-2006-116518).
As is well known, a Venturi tube has in its middle a narrow restriction or throat, and on the water supply side (upstream side) of the throat there is a narrowing tapered section whose diameter narrows gradually as it approaches the throat, and on the water drain side (downstream side) of the throat there is a widening tapered section whose diameter widens gradually as it moves away from the throat. In a Venturi tube, water flowing through the throat accelerates and decompresses. Therefore, if one adds a structure that can bring outside air in and towards the throat, small air bubbles may be incorporated into the water flow inside the throat, thus enabling the generation of microbubbles on the downstream side of the throat.
Also, it has been proposed to install a rotary blade for generating a swirl flow on the water drain side of a Venturi tube in order to intensify and stabilize the acceleration and decompression of the water flow in the throat (for example, see Japanese patent document JP-A-2007-21343).
As noted above, previously known microbubble generators employed a Venturi tube as their main component. One reason for adopting the Venturi tube method is that, by incorporating a narrowing tapered section and a widening tapered section, one can expect to maintain the water in the throat in a laminar flow state as much as possible, prevent turbulence, reduce tube resistance, and thereby accelerate the water flow and generate the decompression effect in an efficient manner.
However, manufacture of Venturi tubes requires special, dedicated tools specifically designed for the respective taper angles of the narrowing and widening tapered sections (such as a tapered end mill or a tapered reamer) or processing machinery (such as a circular saw), which pushes up the cost of manufacturing microbubble generators. Needless to say, when a rotary blade is added, processing of the rotary blade itself is relatively difficult, and it will push up the manufacturing cost even further.
Also, with the Venturi tube method, the existence of the narrowing and widening tapered sections makes the apparatus long in the direction of the tube's axis, which naturally makes the microbubble generator as a whole long, which in turn leads to various problems such as difficulty in handling, a large size in its mounted state, and limitation of mounting locations.
The present invention was developed in consideration of the foregoing, and in certain embodiments aims to solve the existing problems and produce microbubble generators that can be manufactured more cheaply and made smaller, by adopting a configuration that can generate microbubbles without relying on the Venturi tube method which requires complicated structures.
Thus, it is desirable to address the limitations in the art.